Chapman professor studies toxic risk in closed mines

Former Chapman University students Jessey Frances (far left) and Natalie Kiwan (far right) sieve samples with workers from United Research Services, a San Francisco-based research group, during a 2011 trip to the Calico Mine in Calico, Calif. COURTESY OF CHAPMAN UNIVERSITY

Abandoned mine sites in California

•There are more than 47,000 abandoned mine sites in the state. 18,580 of these sites are located on public lands managed by the federal Bureau of Land Management.

•There are about 5,200 abandoned mine sites in California with environmental hazards, according to the Bureau of Land Management.

•Abandoned mine sites in Southern California typically pose less environmental hazards than those in Central and Northern California due to less rainfall and a different set of minerals.

Source: Bureau of Land Management, U.S. Department of the Interior; Abandoned Mine Lands Unit, State Department of Conservation

The roughly 47,000 abandoned mines scattered all over California might provoke thoughts of wealth and state history, but Chapman University professor Christopher Kim says many of them are a greater source of worry than wealth.

For the past seven years, the earth and environmental sciences professor has collected and analyzed mine tailings – waste material left by miners after they extract what they need – from outside abandoned gold mines in California. He said toxic metals in those tailings, such as arsenic, can migrate further out because of weathering and erosion.

Environmental hazards at abandoned mine sites include tailings that contain mercury, arsenic and acid mine drainage that threaten water supplies, surrounding communities and habitat, according to the federal Bureau of Land Management. Kim wants to know how much contamination and risk the mine sites pose to humans.

Kim's project started in 2006 as his independent research. Then, in 2008, he received a five-year grant from the National Science Foundation, among other grants through the years, to expand his project. He said human processes like mining speed up and amplify the way these toxic metals reach wind and runoff water, exposing them to humans. Kim also said the mining areas are attractive to off-road vehicle enthusiasts, who may not be aware of what they are breathing.

"We need to learn as much as we can to rationally decide what to do about it," Kim said. "There is a wide range of ways to treat this issue, so doing the basic research needed to prioritize and advise correctly on the best and most cost-effective ways to clean up these areas I think is a worthwhile investment."

Kim said his gold mine research also teaches his students to apply their work to government policy and public communications. Chelsea Ngo, who worked in Kim's lab for two years, simulated stomach fluids for her senior project to show how arsenic consumption affects the human body.

Ngo, a chemistry major at Chapman who graduated in May, said her work in Kim's lab helps people living near mine sites learn more about their potential hazards. Ngo also noted that there are some Orange County communities that are built on what used to be mine sites, such as the Tustin area, Trabuco Canyon and Silverado Canyon.

"If we find certain red flags with concentration or how the arsenic stays within the system, then obviously we have to report that," Ngo, 21, said. "For me, that's what gives it meaning, because you can at least warn them and let them know."

In past years, Kim would round up groups of about six students who work in his lab to collect samples at a gold mine for the weekend. An area they frequented is a gold mine in Randsburg, Calif., which has some of the highest arsenic levels in the continental U.S., he said. He and his students would collect samples, separate them by particle size and measure their surface areas in different ways to determine their toxic levels.

Kim had to halt his field trips about three years ago when federal agencies scaled back or suspended his project's funding. Lately, he and his research team have tested their backlog of samples for toxic materials to see how much risk the materials will pose to humans down the road.

"Many natural things are toxic, in and of themselves," Kim said. "The point at which it becomes toxic is when your exposure rate to it becomes high enough that you exceed (safe limits)."

He is working on bringing his lab students to mine sites again this fall. Until then, he has enough samples to last his team at least another year.

To help his project attain more accurate results, Kim said he is reaching out to national entities like the National Science Foundation, the federal Bureau of Land Management and the National Institute of Environmental Health Sciences for more financial support.

"I am assuming the sequester is holding things up," he said.

Kim said certain things you can do to minimize exposure to these toxic metals would be washing your hands, fruits and vegetables before you eat them, wet-mopping instead of sweeping it to get rid of dust, and minimizing outdoor activity during high winds. Noting that gold mines are "a big part of our state's history," Kim also said some governmental, private and academic institutions are starting to explore the issue further.

"The legacy that these abandoned mine lands leave behind from an environmental perspective is going to be around for a really long time," Kim said.

Related Links

Former Chapman University students Jessey Frances (far left) and Natalie Kiwan (far right) sieve samples with workers from United Research Services, a San Francisco-based research group, during a 2011 trip to the Calico Mine in Calico, Calif. COURTESY OF CHAPMAN UNIVERSITY
Dr. Christopher Kim, associate professor of earth and environmental sciences at Chapman University. COURTESY OF CHRISTOPHER KIM
Chapman University students collect arsenic-rich tailings in Johannesburg, Calif. COURTESY OF CHAPMAN UNIVERSITY
Former Chapman University student James Akau collects gold mine tailings in Mojave, Calif. COURTESY OF CHAPMAN UNIVERSITY
Chapman students James Dale and Morgan Brown (left and middle, respectively) work with Jim Rytuba of the U.S. Geological Survey to collect samples from gravel pits during a 2009 sampling trip to Randsburg, Calif. COURTESY OF CHAPMAN UNIVERSITY

1 of

User Agreement

Keep it civil and stay on topic. No profanity, vulgarity, racial
slurs or personal attacks. People who harass others or joke about
tragedies will be blocked. By posting your comment, you agree to
allow Orange County Register Communications, Inc. the right to
republish your name and comment in additional Register publications
without any notification or payment.